Optimize loop in lint()

[TrevorBurnham]

Re: #193

@amilajack I took a look at the performance here, and found that a surprising amount of the cost of the lint() function is coming from those polyfills.has() lookups, even when polyfills is a very small set (the project I tested this change against has only 3). So the main optimization here is:

Before

• filter rules down to those that aren't polyfilled
• Run remaining rules through rule.isValid()

After

• Make a single pass through the rules instead of using a separate filter step
• Check rule.isValid() before checking for polyfills

This simple change cut the time it takes to run compat/compat against my project by more than half, from ~13s to ~5.5s! 😮

[amilajack]

Thank you so much for this! I'll cut a preminor for this. Also would love if you could update the changelog to describe these changes. Let's add these changes to 3.3.0.

[TrevorBurnham]

Also would love if you could update the changelog to describe these changes.

Sure thing! How does this look? f681f68

[amilajack]

Awesome! Thanks again Trevor!

[amilajack]

Published this to eslint-plugin-compat@next 🎉 🎉 🎉